Method of supplying fuel for engine idling



Dec. 28, 1937. A. MOORE METHOD' OF'V SUPPLYING FUEL FOR ENGINE IDLING Filed March 17, 1932 'A lNvENToR l r//fvj/o/v Woo/"a BY M E ATTORNEYS Patented Dec. 28, 1937 UNITED STATES METHOD F SUPPLYING FUEL FOR ENGINE IDLING Arlington Moore, New York, N, Y., assignor, by mesne assignments, to Maxmoor Corporation, New York, N. Y., a corporation of .Delaware Application March 17, 1932, Serial No. 599,420

3 Claims.

My invention relates to. methods of supplying -fuel to internal combustion engines during engine idling, and the Same has for its object to supply the fuel at a relatively constant rate over a wide range of variation vof the intake depresjsion effecting the introduction of the fuel, Wherevby tol obtain smooth, steady idling operation.

Another object of the invention is to permit a variation of idling speed by controlling the air l0 quantity without variation in the quantity of fuel -fsupplied, rendering the engine idling stable under a broad tolerance of variations.

Another object of the invention is to enable adjustment of the mixture ratio for any desirable idling speed, while maintaining the rate of fuel flow for each adjustment substantially constant. h "This application is a continuation-impart of my application Serial No. 525,992, filed March 28, 1931, Patent No. 2,056,615, Oct. 6, 1936 and 20 ofmy application Serial No. 591,040, filed February 5, 1932, Patent No. 2,037,530, Apr. 14, 1936,

the idling arrangement being illustrated herein associatedwith an ordinary carbureter, although the invention is adapted for use With various 25. types of carbureting'means, such as those disclosed in my said prior applications.

In the accompanying drawing:

Figure 1 is a sectional elevation of one form of device constructed according to and embodying my said invention; and

Fig. 2 is a detail sectional View of a modification, illustrating means provided for manual adjustment of air inlet orifice for control of discharge rate of fuel.

In the drawing, for purposes of illustration, my idling arrangement is shown associated with a carbureter of the ordinary type in which the charge is throttled after admixture of the components thereof. This type of carbureter comlo prises an intake conduit I0, venturi I2, and main fuel jet I4 supplied with fuel from the float chamber I6, the. admixture of fuel and air being effected at the venturi I2, and the mixture controlled by the mixture throttle I8. l

I preferably supply the fuel for engine idling independently of the main fuel supplied at other stages of operation, and at a relatively constant rate notwithstanding variations or fluctuations of intake depression.

To obtain such result I lift fuel in a solid liquid state through duct 20 from the constant level float chamber I6 into the bottom of a horizontal chamber or passage section 22 having a relatively weak pressure reduction therein obtained by venting one end of the chamber 22 through a highly constricted orice 24 located at an intermediate point of the chamber either directly, or through suitable passages, into the intake at the f engine side of the throttle I8, thereby rendering the orifice subject to vthe pressure reduction in 5 the intake conduit at the engine side of the throttle, and by venting the other end of the chamber 2,2 at substantially the same level to the atmosphere through orifice 26 preferably opening into the top of the bowl I6 which is 10 Vvented to atmosphere. This arrangement prevents the orifices 24 and 26 from clogging with dust or dirt.

The pressure reduction developed in chamber 22 at and near idling operation attains a value 15 which is relatively constant compared to the fluctuations in intake depression, this pressure reduction being suflicient to lift the fuel through passage into the chamber 22 at the intake depressions prevailing at and beyond idling oper- 20 ation so that fuel is available at such stages of operation.

The fuel thus lifted forms a fuel level in chamber 22 substantially on a line with orifices 24 and 26 leaving a space above the fuel level for 25 surface vaporization. The fuel surface in chamber 22 is subjected to the vaporizing effect of the air passing through orifice 26, and sweeping over the surface of the fuel to form, apparently, a compressible suspension of fuel in air. The dis- 3o tance between the orifices 24 and 26 is preferably short enough to. prevent the air sweeping over the surface of the fuel in chamber 22 from causing Waves on or other surging of the fuel liable to submerge orifice 24 and cause excessive 35 fuel to pass into the intake. I have found that a desirable length for the chamber 22 is such that the meniscus of the fuel is substantially coextensive with such length, the surface of the fuel from end to end of the chamber being substantially concave. The concave surface of the fuel under tension resulting from capillary effect is less liable to develop waves or other surges therein as a result of the air sweeping thereover, the action of the air in causing fuel vaporization being analogous tol the action of a surface carbureter.

The resulting suspension or mixture is squeezed through the highly constricted orifice 24 into the intake at the engine side of the throttle I8. The orifice 24 serves to meter the fuel component therethrough at a substantially constant rate, the constriction having frictional coefflcients such as to allow the passage of a predetermined quantity of mixture, and no more, irre- For example, in one type of engine the opening 24 was .014" in diameter and opening 26 was .022 in diameter. Satisfactory operation has been obtained with air inlet opening 26 of the order of .020 to .030 in diameter and with a metering orifice 24 of the order of .013 to .016" in diameter. The orifices 24 and. 26 preferably comprise replaceable jets for allowing adjustment of the Orifice sizes, the adjustment of the jet 26 being principally relied on to determine the pressure reduction in the chamber 22, and ybeing also relied on to determine the mixture ratio, so as to obtain the best mixture ratiorfor any desired idling speed; Y

With the metering of idling fuel in the form of air-fuel mixture through the orifice 24 with openings 24 and 26 of about the sizes above specified, I find that the quantity offuel introduced into the intake at engine idling remains substantially constant over a considerable range of variation of the intake depression, giving a smooth, steady idling .even` though thereY be a considerable fluctuation' inl intakeV depression. v The fuel supplied also remains constant when excessive speeds are'attained with closed throttle I8 during engine comedownperiods, thereby preventing undue enrichment ofthe mixture liable to cause loading, crank case oil dilution, afterburning and other evils;

Location of the air inlet orifice 26 at a level above the fuel exit orifice 24 increases the fuel discharged, and location of orifice 26 at a level below orifice 24 decreases the fuel discharged. However to maintain constant fuel flow, it is preferable to have the air inlet' 26 on Valevel with the exit orifice 24.Y

The relative areas ofthe orifices24'and26 are such as to cause the fuel 4to be supplied through orifice 24 notY only at engine idling but also throughout substantially the fractional load range of operation.

In order toV prevent thechamber 22 from flooding and causing now of solid liquid fuel through orifice 24, the passage 20 below the fuel level in chamber I6 is provided with a small metering orifice or replaceable jet 28 which restricts Athe rate of fuel flow su'iciently to maintain a constant fuel level in the chamber 22 under various conditions ofl engine idling operation, insuring the supplying of fuel at a constant rate. With the orifices 24 and 26 of about the diameters of the order above stated, a satisfactory diameter for the orifice 28 has been found to be .018 to .020.

Without the constricted metering orifice 28', erratic fuel flow might at times occur. For example, if the engine is accelerating and the throttle is, suddenly closed, the resulting high depressionY in the intake and fluctuation inl fuel level in chamberV I6 might cause chamber 22 to flood above its normal level, closing the air'inlet 26, and causing an unduly rich discharge of'fuel. The provision of orifice 28 prevents, because of the limited capacity of the orifice to allow fuel flow therethrough, sudden changes in fuel level in the chamber 22, making it possible tomamtain a smooth, uniform idle.

At Fig. 2 I have shown a manual adjustment for air inlet orifice 26a, the orifice being adjusted by a needle valve 30 toV control the pressure reductionr in the chamber 22 and the Yquantity of fuel supplied.

By my invention I am able to maintain the rate of fuel delivery at engine idling substantially constant over a wide range of variation or fluctuation in intake depression, the idling fuel mixture being prevented from becoming too rich, insuring smooth, steady engine idling, and preventing the detrimental effects above referred to.

With my idling fuel arrangement the throttle canbe used to control the idling speed without causingV variation in the rate of fuel delivery into the intake, and by proper selection of the size of the air jet 26 or by adjustment of orifice 26a, Fig. 2, the fuel quantity or mixture ratio can be controlled or adjusted for any idling speed.

Having thus described my invention What I claim and desire to secure by Letters Patent is:

l. Process of supplying charges for internal combustion engines comprising causing air to sweep over a concave meniscus of fuel, and drawing the resulting mixture through a highly constricted orifice subjected atgthe'posteriorside to the pressure reduction inV the intake at the engine side of the throttle, the quantity of air introduced being such as to produce atv high depressions a pressure reduction at the' anterior side of the discharge orifice elevating'the-fuel'to maintain the meniscus at a level in proximity to the air stream passing to saiddischarge orifice.

2. Process of supplying charges for internal combustion engines, comprising causing a stream of air to sweep over a concave-meniscus of' fuel to thereby 'subject the Vfuel tothe surface vaporizing effect of said stream of air, and discharging they resulting mixture through a constrictedoriiice into the region of reduced pressure at the'engine side'of the-throttle, said fuel being elevated by a Vpressurereduction at the anterior side of said discharge orificesufliciently attenuated by the air introduction to maintain atv high intake depressions a fuel level in the form of a concave meniscus in Vproximity to the air stream passing to said discharge orifice. Y

3. Process of supplying charges for internal combustion engines comprising inducing a flow of air through a passage by the pressure reduction in the intake at the engine side of the throttle, producing in a section of said passage, by relative constriction of orifices at the atmospheric and intake pressure reduction ends thereof, a lesser pressure reduction, lifting fuel' by said lesser pressurerreduction at or near'engine idling from Va lower level toV form a fuel level in the form of a concave meniscus in said passage section, subjectingthe fuel at said fuel level' to the action of the air sweeping'thereover toform a fuel-air mixture, and discharging the mixture thus formed through the vconstricted orifice at Ythe intake pressure reductionl end of the passage section to draw the mixture out into a stream of reduced cross-section for promoting fuel vaporization and to meter the fuel component.

Y ARLINGTON MOORE. 

